Distributing mechanism for concrete mixers



Feb. 4, 1941.

C. F. BALL El AL.

DISTRIBUTING MECHANISM FOR CONCRETE MIXERS 5 Sheets-Sheet 1 Filed June 26, 1939 Qrwmto'w Char/e6 Efiall and Louis GCHz'Zkemeier,

Feb. 4, 194-1.

C. F. BALL ETAL DISTRIBUTING MECHANISM FOR CONCRETE MIXERS Filed June 26, 1939 5 Sheets-Sheet 2 54 101 Q M 'r H |HH"" gwumwtom' UharZesIlBall an Louis afiilkemeiez;

c. F. BALL ETAL 0, 78 DISTRIBUTING MECHANISM FOR CONCRETE MIXERS Filed June 26, 1939 -5 Sheets-Sheet 3 Feb. 4, 1941.

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- C. F. BALL El" AL DISTRIBUTING MECHANISM FOR CONCRETE MIXERS Feb. 4, 1941 Filed June 26, 1939 5 Sheets-Sheet 4 grwv/wbo ay U/mrles 17,501 I and Feb. 4, 11. c F BALL r 2,230,478

DISTRIBUTING MECHANISM FOR CONCRETE mxrms Filed June 26, 1959 5 Sheets-Sheet 5 Z] me/rvbo m 67101'165 EB a N and Lqm's Gifiikemsiez;

Patented Feb. 4, 1941 UNITED STATES PATENT OFFICE DISTRIBUTING MECHANISM FOR CONCRETE MJXERS Wisconsin Application June 26, 1939, Serial No. 281,300

8 Claims.

The invention relates to distributingv mechanism for concrete mixers, and has for one of its objects to provide improyedconcrete distributing mechanism of the boom. and bucket type such as is Widely used in connection with. paving mixers.

In thelaying of concrete roads and streets in accordance with present day practice, the most widely used apparatus is a specialized type of concrete mixer, known as a paver, ordinarily mounted on crawler treads for travel on the subgrade, and embodying a rotatable drum capable of receiving and mixing batches of a cubic yard or more. It is also customary to provide them with apparatus for distributing the mixed concrete over considerable areas, in the form of a horizontal boom, of from 20 to feet in length extending rearwardly from adjacent the discharge opening of the mixing drum and supporting a bucket mounted for reciprocatory traverse thereon. The end of the boom adjacent the drum is pivotally mounted for both horizontal and vertical swinging movements, which may be accomplished at the will of the operator through suitable manual or power operated mechanism; and the bucket is traversed back and forth along the boom by one or more ccbles, also usually power operated, under the control of the op.- erator.

The buckets, are normally of a size suificient to hold a complete batch from the mixing drum, which they receive from the discharge chute through their open top, and are provided at their bottom with pivoted gates or doors which are retained in closed position by various forms of 35'; latches which are capable of being tripped by the operator at will to release the doors and permit the concrete in the bucket to be discharged by gravity through the bottom opening.

Inthe construction of present day high-speed roadways, the tendency is to eliminate curves as far as possible, or to make them of very long radius. However, it is not always feasible to do this, and when circumstances dictate the construction of a curve in the road of. less than a J certain radius, it is customary to bank or elevate the outside of the curve. When a paver is working on the sub-grade of such a banked or elevated curve, with its longitudinal axis parallel to the length of the roadway, the paver is of necessity tilted sideways, and since the boom of the distributing mechanism is connected to the paver frame, it also is tiltedv or canted sideways. In most of the prior constructions, although the buckets have of course been mounted forlongitudinal traverse on the booms, no provision has been made for transverse movements of the buckets relative to the booms, with the result that when such prior pavers were working on banked or elevated curves the buckets were also canted sideways, with consequent undue strain and wear upon the parts, and an increase in the power required to operate them.

It is one of the principal objects of the present invention to provide a construction which will overcome this difficulty, and to this end the invention includes among other things a pivotal suspension of the bucket relative to the boom whereby the latter may tilt or cant sideways While the bucket maintains a perpendicular position.

A further object of the invention is to provide an improved latch mechanism and operating connections for the bucket door, which will accommodate such relative transverse movements between the boom and bucket, and which, while effectively maintaining the bucket door closed until tripped, may be tripped by merely reverse ing the direction of travel of the bucket towing cable. The door is closed and the latch re-set automatically during the return of the bucket to the mixer drum for a fresh batch by cam means on the boom which co-operate with an angular or bell crank lever constituting a portion of the latch mechanism, which lever carries a plurality of rollers which successively engage with said cam means.

With the above and other objects in view, which will appear as the description proceeds, the invention consists in the novel details of construction and in the novel combinations and arrangements of parts, more fully hereinafter disclosed and particularly pointed out in the appended claims.

Referring to the accompanying drawings forming a part of this specification, in which like reference characters designate like parts in all the views- Figure 1 is a side elevational view, partly broken away and in section, of the discharge end of a well known form of paving mixer equipped with boom and bucket distributing mechanism constructed in accordance with the present invention, the parts being illustrated in the closed position of the bucket door;

Fig. 2 is an enlarged elevational view, partly in section, of the boom and bucket shown in Fig. 1, as seen from the left of said figure;

Fig. 3 is an enlarged side elevational view, partly in longitudinal section, of the bucket and a portion of the boom, showing the parts in the tripped or open position of the bucket door;

Fig. 4 is a still further enlarged detail sectional elevational view, taken approximately on the plane indicated by the line 4-4 of Figure 2, looking in the direction of the arrows, and showing the latch mechanism in latched position;

Fig. 5 is a view similar to Fig. 4, but taken approximately on the plane indicated by the line 5-5 of Figure 2, illustrating in full lines the parts in their tripped positions, and in broken lines an intermediate position which they assume in the course of the automatic resetting operation;

Fig. 6 is a perspective view of the bell crank lever constituting a portion of the door operating and latch mechanism;

Fig. 7 is a perspective view of the towing bracket which is mounted upon the bucket carriage; and

Fig. 8 is a detail perspective view of the latch.

Referring more particularly to Figure 1 of the said drawings there is illustrated the discharge end of a typical concrete mixer of the paving type comprising a frame It mounted upon crawler treads H and having a mixing drum I2 rotatably mounted therein upon rollers I3. Said drum has a discharge chute l4 and sub-chute I5 associated with its discharge opening and said discharge chute l4 may be operated by suitable power means (not shown) in accordance with usual paving mixer practice.

The said mixer also has associated with its discharge end bucket and boom distributing mechanism for the mixed concrete comprising boom 20 here shown as being composed of a pair of horizontally extending spaced channels 2| which are pivotally mounted as at 22 adjacent the end next the mixer in a caster 23 whereby the boom may be oscillated upwardly and downwardly in a vertical plane by means of block and tackle mechanism 21. The caster 23 is journalled in a vertical bearing 24 carried by a portion of the mixer frame l9 so that the caster and boom may be swung horizontally about the vertical axis by means of a worm gear 25, and worm 26, which latter may be either manually or power operated. One form of mechanism for power operation of this worm is disclosed and claimed in our copending application filed June 26, 1939, Serial No. 281,298, entitled Boom swinging mechanism for concrete mixers.

The concrete distributing bucket 30 is mounted by means of a trolley or carriage 3| for longitudinal traverse upon the boom 20 by means of draft cables 32 which extend over suitable pulleys or sheaves 33 to a winding mechanism 34, here shown more or less diagrammatically, of any appropriate construction. An example of power operating mechanism suitable for actuating the cables 32 may be found in our co-pending application filed June 26, 1939, Serial No. 281,299, and entitled Boom and bucket distributing apparatus for concrete mixers.

As best shown in Figs. 1, 2 and 3 of the drawings, the bucket carriage 3! may be fabricated from metal plates or sheets and as here shown comprises a plate 35 bent to a channel or U-shape cross section and which is provided upon its outer face with suitable transverse strengthening ribs or webs 36 which may be Welded to the channel 35. Each of the upstanding legs of the channel member 35 is provided with a pair of stub shafts 31, one adjacent each end of the channel and projecting inwardly, upon which shafts are journaled the rollers 33 adapted to engage and run upon the lower flanges of the channel members 2| of the boom 20, as will be readily understood from the said drawings.

A pivot pin 40 is mounted in a pair of the ribs or Webs 36 of the carriage, extending longitudinally of the latter and below the same. Upon this pin is journalled a fabricated transverse suspension structure 4| which is welded or otherwise rigidly secured to the top of the bucket 30 as will be readily understood from Figs. 1, 2 and 3. It thus results that the bucket is pendulously hung from the carriage 3| in such manner as to permit of relative transverse movements between the two.

In Fig. 2 the parts are illustrated in the positions they normally occupy when the paver is operating upon level ground, with the longitudinal axis of the boom 20 lying in the vertical plane indicated by the line A. However, should the paver be moved to sloping ground as upon a banked or elevated curve so that it will be tilted sideways, then the longitudinal axis of the boom will likewise be tilted out of the vertical to a plane such as that indicated by either of the lines B of the said figure. However, notwithstanding this transverse tilting of the boom the bucket obviously will maintain a perpendicular position such as that illustrated in Fig. 2 because of its pendulous mounting upon the pivot pin 40 of the carriage 31. This maintenance of the bucket in truly vertical position not only relieves strain and wear upon the parts but also permits of discharge of its contents uniformly across its width rather than having such discharge shifted toward one corner or the other depending upon the direction in which the paver is tilted.

The bucket 30 is provided with an open bottom through which the concrete is discharged by gravity as is customary in such apparatus, and the discharge opening is controlled and normally closed by a gate or door 50 pivoted as at 5| to the bucket. For retaining said door 50 in closed position during filling and outward movement of the bucket the following mechanism is provided. A pair of links 52 are pivotally connected as at 53 to opposite sides of the door 50 and extend upwardly through suitable guides 54 mounted upon the outer face of the side wall of the bucket. The upper end of each link 52 is rigidly connected to a rod 55 which extends through the bottom of a U-shaped strap member 56 the upper ends of which are pivotally connected as at 5'! to arms 58 rigidly carried by'a transverse shaft 59 which is journalled in suitable bearings 60 mounted upon the forward face or wall of the bucket 30. At the center of the bucket the shaft 59 rigidly carries another pair of arms 6| the outer ends of which are pivotally connected as at 62 to the trunnion member 63 of a universal joint 64. Said universal joint 64 is connected by rod 65 which extends upwardly to a second universal joint 66, the trunnion member 61 of which is pivotally connected as at 68, to the bifurcated arm 59 of a bell crank lever 10. Said lever 10 is pivoted at H to a pair of ears 12 rigidly carried by the carriage 3|. The said bell crank lever is further provided with an angularly extending bifurcated arm 13, which journals a pair of rollers 14 and 15 substantially as shown. The said bell crank 10 is further provided with an inclined rigid finger 75 extending in a plane substantially parallel to that of the arm 13, as will be readily understood from Figures 4, 5 and 6.

Rigidly mounted-upon thecarriage 3i incooperative relation to the bell crank 10 is a towing block 80 which, as will be readily understood from Fig. '7, comprises a base member 3| and a pair of 5 spaced longitudinal extending ribs 82 which extend outwardly above the ears or lugs 72 on the front face of the carriage and each of which is provided with a pair of spaced. laterally extending lugs or projections 33 andtd, which are oppositely inclined substantially as shown. A pair of draft links 85 ispivotally mounted upon the pin H which supports the bell crank, which links extend upwardly within the spaces between the lugs 83 and 8d of towing block 80 as clearly shown in Figs. 2, 3 and 4. The upper ends of these draft links 86 embrace and are pivotally connected as at 81 to a suitable cable connector 88 by means of which the draft cables 32 are connected to the said links.

A latch member 90 is pivotally mounted as'at 9| between the draft links 86 intermediate their ends, which latch as best shown in Figs. 4 and 8, is recessed as at 52 to provide a toe 93 which is adapted to engage with the finger 16 of the bell crank lever Hi, as clearly shown in Fig. 4.

Going back to the links 52 and the U-shaped strapmember 55 of the bucket door operating and controlling mechanism, the rods 55 which extend upwardly from the links 52 are surrounded by helical springs lili! which are confined between the closed end of the strap member 55 and a plate or seat member I91 which is slidably mounted within the U-shaped strap 5%. Said springs Hill are pre-loaded or compressed by means of the adjusting nut 32 to a point sufiicient to withstand the weight of any batch of concrete which the bucket may hold so that the door will be maintained tightly closed at all times, except when the latch mechanism has been tripped, as will be hereinafter explained. The said links 52 are also provided with adjustable stop members H34 which may be positioned at different points along the length of the links by means of the series of openings I05 provided in the said links for the reception of the pins I06 by means of which the stop members I64 are secured to the said links. These stop members I04 are adapted to engage rubber or other resilient buffers I01 which normally rest upon the flanges of the 150 guide members 54 and thereby cushion the shock of the opening of'the bucket door as will be readily understood. By adjusting the position of the stops ms the degree of opening of the door may be controlled.

In operation when the bucket is at the inner end of the boom in position to receive a batch of concrete from the drum E2, the latch and door controlling mechanism are in the positions illustrated in Figs. 1, 2 and 4, with the too 93 of the latch El! in engagement with the finger '15 of the bell. crank Iii. Inthis condition if the draft cable 32 be operated by the mechanism. 34 to move the bucket toward the leftas viewed in Fig. 1, or toward the right as viewed inFig. 4, the motion will be transmitted through the connector-88 and pivotal connections 87 to the draft links 86, which being in engagement with the lugs 83 of the towing block Bil, will draw the carriage 3! and consequently the bucket 35) in the directions above indicated. This traverse of the carriage and the bucket along the boom will continue until the point has been reached at which it is desired-to discharge the contents of the bucket, whereupon by causing the winding mechanism 34 to reverse the direction of travel of the draft cable 32 the. reversed motion thereof will be transmitted throughthe connectorBB and pivotal connectionssl to the :draft links 86 which will cause'the latter'to swing'in a counterclockwise direction .as viewed in Fig. 4,unti1 they engage the lugs 84 of the towing block-8i) which position is illustrated at Figs. 3 and 5. During this movement .of the draft links 86, which is lost motion so far as bucket traverse is concerned, the latch 9!! has, through its engagement with the finger 15 of the bell'crank 10, caused the latter to move in a counterclockwise direction about its pivot H. It will be noted from Fig. 1 that in the normal closed position of the door-5ll the pivot 68 of the universal joint 86 lies to the right of a straight line between the pivot ll of the bell crank and the pivot- 62 of the lower universal 66, so that a toggle 'actionis-had which resists the tendency of the door 59 to open under its own weight or that of the bucket contents. That is to say, in the position shown in Figs. 1 and 4 any tendency of the-door to open and thus move the links 52' and straps 56 downwardly and the armsbl and rods 65 upwardly tends to cause a counterclockwise rotation of the bell crank Ill as viewed in Fig. 1, ma clockwise rotation of it as viewed in Fig. 4, which tendency however will be overcome by reason of the engagement of the arm 69 of the bell-crank lever 10 with a stop block or member H99 carried by the endribtii'of the carriage 3|.

It therefore'follows that the bell crank can not be rotated in this direction to permit thedoor to .open under the weight of theconcrete in the bucket.

However, when the bell crank lever Hi is positively moved in a clockwise direction, as viewed in Fig. 1, during the lost motion movement of draft'links from lugs 83 to lugs-'84, as above described, the pin 68 of universal joint 66 will be moved to the left of the dead center or straight line between pins-62 and I I thereby breaking the toggle, and as soon as this is done the tendency of the demand lower connections to move the bell crank'counterclockwise is reversed and the weight of the door and the bucket contents now tends'to continue the clockwise movement of the bell crankwhich has been initiated by the latch is and :draft links 86. As a result,'the door drops by gravity to the position shown in Fig. 3, discharging the bucket contents, and in so dropping moves the bell crank Ti] and its associated parts to the positions shown in full lines in Fig. 5. During discharge of the bucket contents the :bucket maybe traversed along the boom 20 in eithendirectionwby causing the winding mechanism 3 1 to move the cables '32 in the desired direction, thus permitting the concrete to bespread over'a considerable area instead'of being dumped in'a heap. Such-motion of the cables 32 will be transmitted to thecarriage-Sl by the draft links '86 and lugs 83'or 84 of the towing bracket as, but will have no effect upon the'bell crank it or the door 58 until they are reset.

For closing the door'50 and re-setting the latch mechanism, cam means, here'shown as comprising angle brackets IHJ, Ill and H2 are provided upon the inner face .of one of the boom channels 2! adjacent the inner end of the boom so that the door will be automatically closed and the latch -re-set as the bucket approaches its receiving position. These angle or cam members, as best shown in Figs; 2 and 5, are in position to be engaged by the rollers 14 and 15 carried by the arms 13 of the bell crank 18.

After the parts'have'been tripped to open the bucket door as just described above, they are in the position shown in full lines in Fig. 5. If new the movement of the draft cable 32 be continued toward the left as viewed in said figure to draw the bucket inwardly along the boom toward its receiving position, the roller 15 will be brought into contact with the downwardly inclined surface of the cam or angle member H as shown in full lines in said figure, and as movement of the parts toward the left continues such engagement will cause partial rotation in a clockwise direction of the bell crank lever 10 about its pivot II. This rotation will in turn bring the roller 14 in position to engage the more steeply inclined face of the cam or angle member III, as indicated in broken lines in Fig. 5, and as the draft movement of the cable 32 continues the parts will ultimately be restored to the positions shown in Figs. 1 and 4. As the bell crank 10 moves in the clockwise direction during the re-setting operation its finger l automatically enters the recess 92 of the latch 90 and is brought into engagement with the toe 93 of the said latch as the parts reach the closed position of the bucket door.

In the innermost position of the bucket, in which it receives the concrete from the discharge chute [4, the roller 14 is under the angle member I I2 on boom 2|], which prevents unintentional tripping of the bell crank and opening of the door so as to discharge the concrete in this closein position.

As above indicated, the springs I60 which are interposed between the bottom of the U-shaped strap members 56 and the spring plates IOI are pre-loaded or compressed sufficiently to withstand the weight of any batch of concrete which may be within the bucket. The parts are so constructed and arranged that during the closing movements of the door 50 it reaches its seated position against the bottom of the bucket slightly before the bell crank 10 and its associated parts have reached the toggle-locked positions shown in Figs. 1, 2 and 4. As the bell crank continues its movement after the door is thus seated its motion is transmitted through the universal joint 66, connecting rod 65, universal joint 64, arms 6|, shaft 59 and arms 58 to the strap members 56, and since the door 50 and links 52 can move no further in an upward direction the strap members 58 cause a further compression of the springs I00. The purpose of this is to accommodate or compensate for relative movements between the bucket and carriage about the pivot pin 40. That is to say, since the bucket is not in any ways restrained against swinging upon the pivot pin,

even though the paver and boom may not be tilted sideways, when such swinging movements of the bucket take place during its outward travel, they will have a tendency to cause clockwise movement of the arms BI and 58, as viewed in Fig. 1, which is the direction in which these arms move as the bucket door opens, and if the connections between the arms 58 and the door 59 were rigid the latter would be slightly opened and permit leakage at least of the more liquid constituents of the mixture. However, with the provision of the pre-loaded springs I90 should such movement of the arms 58 and 80 occur by reason of swinging of the bucket upon the pivot pin 40 the springs will expand and maintain the door tightly closed and thus prevent such leakage.

While one form of the invention has been illustrated and described it is obvious that those skilled in the art may vary the details of construction as well as the precise arrangement of parts without departing from the spirit of the invention and therefore it is not wished to be limited to the above disclosure except as may be required by the claims.

What is claimed is:

1. Mechanism for actuating the dischargecontrolling door of the distributing bucket of a concrete mixer, said bucket being attached to a carriage traversable upon a boom extending from the mixer frame and subject to transverse canting movements thereof, there being a longitudinal pivotal connection between the bucket and carriage to accommodate said canting movements of the boom while the bucket remains perpendicular; said mechanism comprising a lever pivoted upon the carriage and provided with means engageable during traverse of the carriage upon the boom with a portion of the boom to impart movement to the lever; thrust-transmitting linkage carried by the bucket, extending from said lever to the bucket door and connected therewith; and a pivotal connection between said linkage and lever disposed adjacent the longitudinal pivotal connection between the bucket and carriage.

2. Mechanism for actuating the dischargecontrolling door of the distributing bucket of a concrete mixer, said bucket being pendulously pivotally connected to a carriage traversable upon a boom extending from the mixer frame and subject to transverse canting movements of the latter, the axis of said pivotal connection extending longitudinally of said boom whereby the bucket may maintain a perpendicular position when the boom cants transversely; said mechanism comprising a substantially L-shaped lever pivotally mounted upon the carriage, one arm of which is provided with means engageable during traverse of the carriage in one direction with a boomcarried element to impart movement to the lever in one direction; thrust-transmitting linkage carried by the bucket, extending from said lever to the bucket door and connected to the latter; and a universal pivotal connection between said linkage and the other arm of said lever disposed 1 3. Mechanism for actuating the discharge-controlling door of the distributing bucket of a concrete mixer, said bucket being pendulously pivot ally connected to a carriage traversable by reciprocating means upon a boom extending from the mixer frame and subject to transverse canting movements of the latter, the axis of said pivotal connection extending longitudinally of said boom whereby the bucket may maintain a perpendicular position when the boom cants transversely; said mechanism comprising a substantially L-shaped lever pivotally mounted upon the carriage, one arm of Which is provided with means engageable during traverse of the carriage in one direction with a boom-carried element to impart movement to the lever in one direction; linkage carried by the bucket, having a portion thereof connected to the bucket door; a pivotal connection between another portion of said linkage and the other arm of said lever, disposed adjacent the longitudinal pivotal connection between the bucket and carriage, whereby to accommodate the transverse canting movements of the boom relative to the bucket; a finger rigidly carried by said L-shaped lever; a draft link'pivotally mounted on the carriage and connected to said reciprocating means; and a latch member carried by said draft link, engageable with said finger upon movement of the link in one direction to impart movement to said finger and L-shaped lever in a direction opposite to that imparted thereto by the boom-carried element.

4. In boom and bucket type distributing mechanism for concrete mixers, the combination with a boom supported by the mixer frame and subject to transverse tilting movements thereof, a bucket carriage mounted for longitudinal traverse on said boom, and a bucket pivotally connected to said carriage to accommodate relative movement between the two about an axis substantially longitudinal of the boom, said bucket having a discharge controlling door, of operating mechanism for said door comprising a portion mounted on said carriage, a portion mounted on the bucket and connected to the door, and pivotal connections between the two portions adjacent the pivotal connection between the bucket and carriage, said bucket-carried portion being subject to movements tending to undesirably open said door as a result of relative movement between the bucket and carriage about said longitudinal aXis; and means for preventing such undesired opening of the door.

5. In boom and bucket type distributing mechanism for concrete mixers, the combination with a boom supported by the mixer frame and subject to transverse tilting movements thereof, a bucket carriage mounted for longitudinal traverse on said boom, and a bucket pivotally connected to said carriage to accommodate relative movement between the two about an axis substantially longitudinal of the boom, said bucket having a discharge controlling door, of operating mechanism for said door comprising a portion mounted on said carriage, a portion mounted on the bucket and connected to the door, and pivotal connec tions between the two portions adjacent the pivotal connection between the bucket and carriage, said bucket-carried portion being subject to movements tending to undesirably open said door as a result of relative movement between the bucket and carriage about said longitudinal axis; and resilient means included in the bucket-carried portion of said operating mechanism for counteracting the movements thereof induced by said relative movements between the bucket and carriage, and thereby preventing such undesired opening of the door.

6. In boom and bucket type distributing mechanism for concrete mixers, a boom supported by the mixer frame; a bucket carriage mounted for longitudinal travel upon said boom; a bucket mounted by said carriage, having a discharge controlling door; a lever pivotally mounted on said carriage, having a latch engaging member; operating connections between said lever and door; draft links pivotally mounted on said carriage; a latch carried by said draft links arranged to co-operate with said engaging member to move said lever in one direction; means for oscillating said draft links upon their pivots; and a towing bracket mounted on said carriage, having spaced driving lugs arranged to provide 10st motion driving connections with said draft links, whereby movement of said lever may be initiated in one direction by said latch and engaging member through lost motion movement of said links in one direction.

7. An element for control mechanism for the door of a concrete distributing bucket, comprising a substantially L-shaped lever having a journal at substantially the junction of the arms whereby it may be pivotally mounted, one of said arms being connectible through linkage with the door, and the other of the arms carrying members mounted intermediate its ends and at its free end for serial engagement with a resetting cam, said lever also having a latch-engaging finger extending therefrom laterally adjacent the second mentioned arm.

8. A towing member for the buckets of concrete distributing mechanism of the boom and bucket type, comprising a bracket rigidly attachable to the bucket assembly and having an up-standing web provided with a pair of laterally extending vertically converging separated lugs providing a space between for the reception of a pivoted draft link which may have alternate lost-motion engagement with said lugs as it is oscillated on its pivot.

CHARLES F. BALL. LOUIS G. HILKEMEIER. 

